Seating for the screw spindle and guide means for the sliding contact wire in a glass tube thermometer of round,non-circular or polygonal cross section and containing adjustable electrical contact means for temperature

ABSTRACT

A seating for the screw spindle and a guide means for the sliding contact wire in a glass tube thermometer of round, noncircular or polygonal cross section and containing adjustable electrical contact means for temperature control and/or limitation. The seating for the screw spindle provided for setting the required temperature has a pan-shaped bottom and resilient blades forming the sides of the seating, one of the blades having an extension bent over inwards into parallelism with the pan-shaped bottom to form a lug containing a hole in which the lower end of the screw spindle is eccentrically or centrically held, whereas another of the blades is likewise extended but the extension bent over outwards into parallelism with the blade itself. The bend contains an opening and the blade itself a corrugation which in cooperation with the extension and together with the hole forms a tubular guideway for the electrical contact wire.

United States Patent 191 Juchheim et a1.

[11] 3,745,501 July 10, 1973 of Germany [73] Assignee: Moritz K. Juchheim, Fulda, Germany [22] Filed: Dec. 29, 1971 [21] Appl. No.: 213,648

[30] Foreign Application Priority Data June 1, 1971 Gennany P 21 27 039.3

[52] US. Cl 337/122, 337/327, 337/330, 337/331 [51] Int. Cl. 1101b 61/00 [58] Field of Search 337/122, 312, 319, 337/327, 329, 330, 331

[56] References Cited UNITED STATES PATENTS 2,459,968 1/1949 Schwartz 337/331 X Primary Examiner-Bernard A. Gilheany Assistant ExaminerF. E. Bell Att0rney-Neil F. Markva et a1.

[57] ABSTRACT A seating for the screw spindle and a guide means for the sliding contact wire in a glass tube thermometer of round, non-circular or polygonal cross section and containing adjustable electrical contact means for temperature control and/or limitation. The seating for the screw spindle provided for setting the required temperature has a pan-shaped bottom and resilient blades forming the sides of the seating, one of the blades having an extension bent over inwards into parallelism with the pan-shaped bottom to form a lug containing a hole in which the lower end of the screw spindle is eccentrically or centrically held, whereas another of the blades is likewise extended but the extension bent over outwards into parallelism with the blade itself. The bend contains an opening and the blade itself a corrugation which in cooperation with the extension and together with the hole forms a tubular guideway for the electrical contact wire.

5 Claims, 2 Drawing Figures SEATING FOR THE SCREW SPINDLE AND GUIDE MEANS FOR THE SLIDING CONTACT WIRE IN A GLASS TUBE THERMOMETER OF ROUND, NON-CIRCULAR OR POLYGONAL CROSS SECTION AND CONTAINING ADJUSTABLE ELECTRICAL CONTACT MEANS FOR TEMPERATURE BACKGROUND OF THE INVENTION This invention relates to a seating for the screw spindle and a guide means for the sliding contact wire in a glass tube thermometer of round, non-circular or polygonal cross section and containing adjustable electrical contact means for temperature control and/or limitation.

The bottom bearing of the screw spindle carrying the travelling nut in mercury-in-glass thermometers that are provided with an adjustable electrical contact for temperature control and/r limitation is traditionally a ceramic or solid metal seating for the pointed end of the screw spindle. The sliding contact in such an arrangement comprises a platinum coil inserted in a curved glass tube or an unsupported coiled spring contacting the contact wire at several points.

In order to avoid the well known defects of this arrangement a sheet metal cage has already been developed for seating the screw spindle, but although this has considerable advantages over the traditional arrangement it is necessary for the glass tube to have an oval cross section. In view of the fixation needed for an additional sliding contact wire suspended between the screw spindle seating and an upper guide means, the necessary stamping element is a very complex element which requires several operations for its production. Another drawback of this form of construction is that oval glass tubes are difficult to obtain and any quantity of such tubes always includes considerable tolerational variations from a maximum to a minimum diameter. It follows that the travelling nut which is likewise oval must allow for a correspondingly large clearance in the glass tube. This in turn necessitates the provision of a special loop and loop tapping arrangement to the stationary sliding contact wire.

Furthermore in the classical as well as in the aforedescribed cage-type seating the interception of particles that rub loose from the screw and/or the travelling nut is not 100 percent reliable and such matter entering the mercury filling is liable to cause functional difficulties.

SUMMARY OF THE INVENTION It is the object of the invention to eliminate these and other shortcomings inherent in known arrangements.

To attain this object the present invention provides a seating for the screw spindle and a guide means for the sliding contact wire in a glass tube thermometer of round, non-circular or polygonal cross section and containing adjustable electrical contact means for temperature control and/or limitation, which comprises a panshaped bottom and resilient blades forming the sides of opening and said other blade a corrugation which in cooperation with the extension and together with the opening in said bend forms a tubular guideway for an electrical contact wire.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing shows a screw spindle 1 for adjusting the required temperature, which is mounted inside a round section glass tube 2, its lower end being held in a spindle seating 3 as proposed by the invention, whereas its upper end works in a conventional bearing not shown in the drawing. The travelling nut which is likewise not shown works on the screw spindle 1 in as eccentric a position as possible. The spindle seating 3 is provided in the region of a constriction in the glass tube 2 between the upper end of the glass tube 2 and the capillary and comprises a pan-shaped bottom 4 which has an annular edge 4' from which an annulus of resilient blades 4" extend in the upward direction and resiliently bear against the inside wall of the glass tube constriction. This arrangement has the advantage of allowing some tolerational variations in the dimensions of the glass tube constriction and of nevertheless providing a secure bearing for the screw spindle 1 inside the constriction and preventing the passage of dirt. The lower pointed end 1' of the screw spindle 1 stands on the pan-shaped bottom 4 and is secured against lateral displacement from its eccentric position by being passed through a hole in a bearing lug 5 forming an extension of one of the blades 4" bent over at about If a non-circulanoval or polygonal glass tube is to be used, the cross section of the proposed pan-shaped screw spindle seating must be adapted thereto in shape.

Naturally the pointed end 1 of the screw spindle 1 may also engage in a recess or in a bore in the bottom 4 of the seating 3.

Another possible arrangement would be to locate the bearing lug 5 slightly lower nearer the bottom 4 and parallel thereto (not shown) to ensure that any dirt will definitely be collected in the spindle seating 3.

For the passage of an electrical contact wire of the blades 4" is provided with a corrugation 7 impressed into said blade in the direction towards the pointed end 1' of the screw spindle 1. This blade 4" also has an extension which is bent over at and forms a strap 8. An opening 9 is provided in the bend connecting the corrugation 7 and the strap 8 for the passage therethrough of the contact wire 6 which simultaneously slides through the tubular passage created between the corrugation 7 and the strap 8, so that it makes sliding contact with the spindle seating 3 at least at two points. This ensures the maintenance of satisfactory electrical contact.

By this arrangement all the conditions an unexceptionable seating for the screw spindle should fulfil are fully met without restrictions regarding the employment of round, non-round or polygonal glass tubing. The screw spindle is securely held in a very eccentric and possibly, if desired, in a centric position, protection against the ingress of foreign matter is good and reliable, satisfactory electrical contact of the sliding contact wire is ensured and the entire seating is easy to produce and assemble.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiment is therefore to be considered in all respects as illustrative and not restrictive.

What is claimed is: v

l. A seating for the screw spindle and a guide means for the sliding contact wire in a glass tube thermometer of round, non-circular or polygonal cross section and containing adjustable electrical contact means for temperature control and/or limitation, comprising a panshaped bottom and resilient blades forming the sides of the seating, one of said blades having an extension bent over inwards into parallelism with the pan-shape bottom to form a bearing lug containing a hole in which the lower end of a screw spindle is held, whereas another of said blades has an outwardly directed bend followed by an extension extending parallel to said other blade, said bend containing an opening and said other blade a corrugation which in cooperation with the extension and together with the opening in said bend forms a tubular guideway for an electrical contact wire.

2. An arrangement according to claim 1, wherein the lower end of the screw spindle is eccentrically held in the hole of the bearing lug.

3. An arrangement according to claim 1, wherein the lower end of the screw spindle is centrically held in the hole of the bearing lug.

4. An arrangement according to claim 1, wherein the lower end of the screw spindle terminates in a point which engages in the pan-shaped bottom of the seating.

5. An arrangement according to claim 1, wherein the blade extension forming the bearing lug is bent over at a level slightly lower than that of the remaining blades. =1 i 

1. A seating for the screw spindle and a guide means for the sliding contact wire in a glass tube thermometer of round, noncircular or polygonal cross section and containing adjustable electrical contact means for temperature control and/or limitation, comprising a pan-shaped bottom and resilient blades forming the sides of the seating, one of said blades having an extension bent over inwards into parallelism with the pan-shaped bottom to form a bearing lug containing a hole in which the lower end of a screw spindle is held, whereas another of said blades has an outwardly directed bend followed by an extension extending parallel to said other blade, said bend containing an opening and said other blade a corrugation which in cooperation with the extension and together with the opening in said bend forms a tubular guideway for an electrical contact wire.
 2. An arrangement according to claim 1, wherein the lower end of the screw spindle is eccentrically held in the hole of the bearing lug.
 3. An arrangement according to claim 1, wherein the lower end of the screw spindle is centrically held in the hole of the bearing lug.
 4. An arrangement according to claim 1, wherein the lower end of the screw spindle terminates in a point which engages in the pan-shaped bottom of the seating.
 5. An arrangement according to claim 1, wherein the blade extension forming the bearing lug is bent over at a level slightly lower than that of the remaining blades. 